Cortico-Steroid creams are topical and also not very strong. They have the opposite effect of stuff like testosterone, they are used to make your immune system calm down - to stop causing the painful rashes.
They will not affect your recovery as the effect is very local and not systemic. If you swallowed the cream it might cause some problems.
I have also been suffering quite suddenly from some eczema for the past 2 years I have been training. The only reasoning I can come up with is Histamine which is contained in all of the foods I am eating large amounts of. And the possibility of being allergic to one of the many amino acids I am currently ingesting fairly large quantities of.
I am what they call "atopic" you may be too.